Claypool, a popular Democrat who was considered a potential challenger to board president Todd Stroger, is taking direct aim at Cook County Democratic Party Chairman Joe Berrios who won the Democratic primary for the tax office.

"Joe Berrios is a clear threat to homeowners and seniors in Cook County...we're not going to take it anymore," Claypool said in announcing his bid.

2010 Illinois Election Guide

"This race is every bit as important as the race for Cook County Board President," Quigley said. "This is a critical juncture in the county's history."

Jackson called it a "bright day in Cook County politics.

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"I have a profound respect for the party chairman," Jackson said. "But within Cook County the system is so unfair ... and the party that does not acknowledge their unfairness does so at their own peril."

Berrios said Claypool's the one who poses a threat to the Cook County Democrats.

"He's flip, destructive and anti-democratic," Berrios said in a statement. "We will have a fight but i just hope in our battle that we do not destroy the Democratic party."

It should be a doozy.

Claypool has an established record of reform as the onetime head of the Chicago Park District who cut patronage jobs, bucking House Speaker Mike Madigan.

As a first-time candidate for the county board in 2002, he beat Ted Lechowicz, the triple-pension-dipping candidate endorsed by Claypool’s former boss, Mayor Daley. Claypool twice served as Daley’s chief of staff.

Claypool’s first challenge --- one of many for an independent candidate in Cook County – is to collect 25,000 petitions to get on the ballot.